In vitro evaluation of atmospheric particulate matter and sedimentation particles using yeast bioassay system.

Little information on the evaluation of airborne particulate matter (APM) and sedimentation particles from subway stations is available. The thermal metamorphism of train wheels generating toxic particles in subway stations is a possibility. In this study, the toxicity and physiological effects of particles from subway stations were evaluated using a yeast bioassay system. Estrogenic and antiestrogenic activities of APM in APM extracts from subway stations were determined. No estrogenic activity was found in the APM fractions and their S9-activated APM samples. Sedimentation dust samples also showed no estrogen activity. In contrast, extracts from sedimentation dust samples showed antiestrogen activity. Marked yeast toxicity was observed in the samples extracted from sedimentation dust. Potent yeast toxicity was also found in the S9-activated extracts from sedimentation dust. The results suggest that sedimentation dust from a semiclosed area of a subway system has antiestrogen activity, although both the origin and generation system of this activity are uncertain. These pollutants in sedimentation dust may change to a more toxic form in vivo by S9 activation.     

Fertilization success and sexual behavior in male medaka, Oryzias latipes, exposed to tributyltin

We evaluated the effects of tributyltin (TBT), polychlorinated biphenyls (PCBs), and a mixture of TBT and PCBs on reproduction, gonadal histology, and sexual behavior in Japanese medaka (Oryzias latipes). We administered TBT (1 microg g(-1) body weight [b.w.] daily), PCBs (1 microg g(-1) b.w. daily), or both to medaka for 3 weeks. We assessed reproductive success during week 3 and the sexual behavior of male medaka after the exposure period. Fertilization success was significantly decreased in groups that received TBT. The profiles of fertility developed a bimodal distribution in the TBT and TBT+PCBs groups, and the numbers of males that performed "following" and "dancing" were significantly decreased in the TBT+PCBs group. The frequency of "dancing" also decreased after treatment with TBT, whereas fish that received PCBs only showed no difference in sexual behavior. Testes that had oocytes showed normal spermatogenesis, even though two of the five males treated with TBT+PCBs had some indication of testis-ova, which did not occur in any other group. Our results indicate that TBT, but not PCBs, affects sexual behavior and reproduction in medaka.     

Evaluation of 14C abundance in soil respiration using acclerator mass spectrometry

To clarify the behavior of 14C in terrestrial ecosystems, 14C abundance in soil respiration was evaluated in an urban forest with a new method involving a closed chamber technique and 14C measurement by accelerator mass spectrometry (AMS). Soil respiration had a higher Delta14C than the contemporary atmosphere. This indicates that a significant portion of soil respiration is derived from the decomposition of soil organic matter enriched in 14C by atmospheric nuclear weapons tests, with a notable time lag between atmospheric 14C addition and re-emission from soil. On the other hand, delta14C in soil respiration demonstrated that 14C abundance ratio itself in soil-respired CO2 is not always high compared with that in atmospheric CO2 because of the isotope fractionation during plant photosynthesis and microbial decomposition of soil organic matter. The Delta14C in soil respiration was slightly lower in August than in March, suggesting a relatively high contribution of plant root respiration and decomposition of newly accumulated and/or 14C-depleted soil organic matter to the total soil respiration in August.     

Air pollution by concrete dust from the Great Hanshin Earthquake

Air pollution in the areas affected by the Great Hanshin Earthquake (Hyogo, Japan) of 17 Jan. 1995 was quite serious. We performed three investigations of dust. In the first investigation, we measured the total suspended particulate (TSP) concentration in the greatly damaged areas, located around the Sannomiya Station where a few hundred thousand people walked by during the daytime of 3 February. The maximum concentration at five points reached 150 microg/m3. In the second investigation, eight samples, which were classified into three groups (concrete, mortar, and soil dusts) as sources, were analyzed elementally by X-ray fluorescence. The elements found in concrete dust (Ca and S) were similar to those found in mortar dust. These differed from those found in soil dust (Ti, Fe, and Zr). The elements found in soil dust were important from the viewpoint of heavy metal contamination. In the third investigation, the alkalinity of concrete dust was observed by dissolution. This solution was equivalent to pH 11 to 12 and electrical conductivity 20 to 30 microS/m. We suspect that the alkaline component in the dust from debris in all the devastated areas was approximately comparable with the alkaline solution by which the acid rain falling over the Hanshin district of Osaka Megalopolis in one year could be neutralized into water of pH 7.0.     

两性修饰磁化炭对紫色土吸附菲的增强作用

为了验证两性修饰磁化炭材料对紫色土吸附菲的增强作用,采用共沉淀负载Fe_3O_4法和湿法有机负载分别制备了磁化炭(MC)和不同十二烷基二甲基甜菜碱(BS-12)修饰比例的两性修饰磁化炭(BS+MC),将其以1%的质量比加入到紫色土(PS)中,分别形成PS_(MC)和PS_(BS+MC)混合样品,批处理法研究各混合样品对菲的等温吸附和热力学特征,并对比了不同温度、离子强度和pH值对菲吸附的影响。结果表明:(1) MC和BS-MC材料的添加均增强了PS对菲的吸附能力,菲吸附量呈现PS_(200BS+MC)> PS_(150BS+MC)> PS_(100BS+MC)> PS_C> PS_(MC)> PS_(50BS+MC)> PS_(25BS+MC)> PS的趋势,PS_(BS+MC)对菲的吸附量随着添加材料上BS-12修饰比例的增加而增加。(2)菲在各供试土样上的吸附均表现为增温负效应(物理吸附),溶液pH值变化仅对PS_(150BS+MC)和PS_(200BS+MC)吸附菲有显著影响。离子强度增大不利于各供试土样对菲的吸附。(3) Henry模型适用于描述菲在供试土样上的等温吸附,且该过程呈现自发的、焓减和熵增的特征。从PS_C到PS_(MC)再到PS_(BS+MC),吸附过程呈现自发性、放热量和混乱度均增大的特征。     

Recovery of coagulant from water supply plant sludge and its effect on clarification

Spent coagulant in water supply plant sludge was extracted with H₂SO₄ and the efficiency of the reused coagulant was studied. The optimum pH values for coagulant extraction and clarification with the reused coagulant were 3.0–4.0 and about 6, respectively. In treating raw influent obtained from a sewage treatment plant and wastewater from a coastal landfill site, the removal of chemical oxygen demand (COD), total nitrogen, and total phosphorous with the recovered coagulant was higher than that with commercial aluminum sulfate or polyaluminum chloride. In addition, the sludge settling properties, the extra sludge mass formation, the supernatant quality, and the cost of reagents were also studied. The coagulant recovered from water supply plant sludge by H₂SO₄ extraction could be successfully reused for the clarification of domestic and food industry wastewaters.     

Estrogen content and relative performance of Japanese and British sewage treatment plants and their potential impact on endocrine disruption.

Both the UK and Japan are densely populated islands with relatively short rivers. Therefore, both countries are likely to be highly exposed to contaminants emanating from their human populations. This review considered how effective the different sewage treatment facilities of the two countries are at removing steroid estrogens from the effluent. The methods of estrogen analysis in sewage effluent, the number and importance of different sewage treatment types, and their apparent effectiveness at removing estrogens were all considered. In both countries, the activated sludge treatment was dominant in terms of people served and water discharged. The analytical techniques used by those studying estrogen concentrations in effluents in both countries were broadly similar. Activated sludge plant (ASP) effluent in the UK typically contained around 2 ng/L estradiol (E2) and 8 ng/L estrone (E1), while Japanese ASPs typically reported E2 as below detection, and 10 ng/L E1 in their effluents. When estrogenic bioassays were used in Japan, they typically record an estrogenic potency of 10 ng/L E2 equivalents. Even taking into account ethinylestradiol (EE2) (not found in Japanese effluents), the overall estrogenicity of British sewage effluents would appear to be the same as that of Japanese sewage effluents (around 10 ng/L E2 equivalents). This suggests that the ASPs serving the large urban communities in Japan and the UK would have effluent of similar estrogenic potencies. Less information is available about the more numerous biological (trickling) filter plants (BFP) in the UK and oxygen ditches (OD) in Japan which tend to serve smaller, more rural communities. The available data would suggest that the BFPs are significantly less efficient than the ODs at removing E1. This would suggest that in similar circumstances, British headwaters (where this sewage treatment plant (STP) type is often found) might be more at risk from endocrine disruption than their Japanese counterparts. Overall, the apparently higher incidence of endocrine disruption in British wild fish than in Japanese wild fish cannot be attributed to differences in the efficiency of their respective STPs.     

Pre- and post-hatch trophic egg production in the subsocial burrower bug, Canthophorus niveimarginatus (Heteroptera: Cydnidae)

In recent years, three terrestrial bugs, Adomerus triguttulus and Sehirus cinctus (Cydnidae) and the closely related Parastrachia japonensis (Parastrachiidae), have been the focus of several fascinating studies because of the remarkable, extensive parental care they were found to display. This care includes egg and nymph guarding, production of trophic eggs, unfertilized, low cost eggs that are used as food by newly hatched nymphs, and progressive provisioning of the host seed. In this study, we have investigated yet a third related Asian cydnid, Canthophorus niveimarginatus, with regard to the possible occurrence of some or all of these complex traits in order to assess how widespread these maternal investment patterns are in this group of insects and to better understand the implications of their manifestations from an evolutionary context. Manipulative experiments were carried out in the lab to determine whether females provision nests. Observational and egg removal studies were carried out to determine whether trophic eggs are produced, and, if they are, their possible impact on nymphal success. The findings revealed that C. niveimarginatus does, in fact, progressively provision young, and this species also displays all of the other behaviors associated with extended parental care in subsocial insects. Moreover, unlike the other two related species, which place trophic eggs on the surface of the original egg mass, C. niveimarginatus produces both pre- and post-hatch trophic eggs. Nymphs deprived of access to post-hatch trophic eggs had significantly lower body weight and survival rate than those that fed on them. To our knowledge, this is the first time the production of both pre- and post-hatch trophic eggs has been demonstrated in insects outside the Hymenoptera. In this paper, we qualitatively and quantitatively demonstrate the provisioning behavior and patterns of trophic egg production in C. niveimarginatus. When and how trophic eggs are produced and delivered to young should have important correlations with the ecological and life history constraints under which a species has evolved. Thus, we also discuss the possible ecological and life history factors that favor the evolution of post-hatch trophic eggs.     

Sensitivity of gametes, fertilization, and embryo development of the Japanese pearl oyster, Pinctada fucata martensii, to the harmful dinoflagellate, Heterocapsa circularisquama

Blooms of the toxic dinoflagellate Heterocapsa circularisquama cause massive bivalve kills in Japan. Mariculture of the Japanese pearl oyster, Pinctada fucata martensii, is the industry most affected by these blooms, especially in Ago Bay, Mie Prefecture, where they are frequent, cause mass mortality of oysters, and overlap with their spawning season. The goal of this August 2009 study was to assess the effects of a toxic strain of H. circularisquama isolated from Ago Bay on gametes, fertilization, and embryo development of pearl oysters. Spermatozoa, eggs, spermatozoa and eggs, and fertilized eggs of pearl oysters from Ago Bay were exposed to H. circularisquama at cell densities reported during the bloom (10–10⁴ cells mL^?1) for different periods of time. The concentration of H. circularisquama, exposure duration, and their interactions all had significant effects on gamete quality, fertilization, and embryo development. The motility and swimming velocity of spermatozoa, egg viability, fertilization, and embryo development rate were significantly reduced in all concentrations, with a cell density of 10 cells mL^?1 determined to be the critical density of H. circularisquama for deleterious effects. This is the first evidence of inimical effects of an HAB species on bivalve spermatozoa upon direct exposure. Further field and laboratory studies are required to investigate the potential effects of H. circularisquama blooms on the reproduction and recruitment of Japanese pearl oysters and other bivalves.     

基于系统仿真模拟的三峡库区生态承载力分区动态评价

针对现有生态承载力评价研究中时间动态性、空间差异性考虑不足等问题,引入系统动力学(SD)模型,围绕生态承载力关键指标实施三峡库区分单元的系统仿真模拟和预测,整合生态承载力综合评价方法,对不同控制单元承载力状况进行动态评价. 结果表明:①2010年三峡库区生态承载力指数为0.55,为弱可承载状态. 生态承载力限制因素分析显示,长江嘉陵江重庆市辖区控制单元、长江涪陵区万州区控制单元主要受制于资源、环境要素,其他3个控制单元(澎溪河开县控制单元、长江云阳县巫山县控制单元、长江恩施州宜昌市控制单元)主要受制于社会、经济要素. ②现有发展趋势下,2010—2025年三峡库区生态承载力指数为0.48~0.57,呈先增后减的趋势,拐点出现在2015年附近,整体亦处于弱可承载状态. 2015年后,以资源、环境为主要限制因素的2个控制单元生态承载力指数开始逐年下降;以社会、经济为主要限制因素的其他3个控制单元生态承载力指数则呈延续上升态势. ③综合调控方案下,三峡库区生态承载力指数在2015年达到0.60,由弱可承载提升为基本可承载;至2018年,所有控制单元均达到基本可承载,生态承载力指数为0.60~0.76. 可见,综合调控方案对各控制单元人口、经济、环境、资源因素的调控行之有效.